1. Field of the Invention
The present invention relates to a nonvolatile semiconductor memory device and a data erase/write method thereof, and is applied, for example, to a ReRAM (resistive memory) using a variable resistor element in which a resistance value varies depending on the direction of a voltage that is applied.
2. Description of the Related Art
In recent years, studies have been made on the application of, e.g. a ReRAM (resistive memory) using a variable resistor element in which a resistance value varies depending on the direction of a voltage that is applied. As disclosed in, for instance, Jpn. Pat. Appln. KOKAI Publication No. 2004-272975 and S.Q. Liu, N. J. Wu, A. Ignatiev (App, Phy, Lett, 76, 19 (2000), such a phenomenon was found that when a voltage pulse is applied to a thin film, which becomes a variable resistor element, the resistance value of the thin film remarkably varies depending on the direction (sign) of the pulse voltage, and this phenomenon is applied to memories.
Jpn. Pat. Appln. KOKAI Publication No. 2004-272975 discloses an example of a nonvolatile semiconductor memory device using a variable resistor element. In the structure of KOKAI No. 2004-272975, however, only one select transistor (Si), which selects a series-connected memory cell section (memory cell string) (2), is provided in association with each series-connected memory cell section (2).
Thus, there is a tendency that the direction of the voltage that is to be applied to the variable resistor element cannot be changed, and data erase (reset) cannot be executed in units of the series-connected memory cell section (memory cell string) (2).